1 files changed, 42 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/attributes/aliasing.rb b/activerecord/lib/active_record/attributes/aliasing.rb
new file mode 100644
index 0000000000..db77739d1f
--- /dev/null
+++ b/activerecord/lib/active_record/attributes/aliasing.rb
@@ -0,0 +1,42 @@
+module ActiveRecord
+  module Attributes
+    module Aliasing
+      # Allows access to keys using aliased names.
+      #
+      # Example:
+      # class Attributes < Hash
+      #   include Aliasing
+      # end
+      #
+      # attributes = Attributes.new
+      # attributes.aliases['id'] = 'fancy_primary_key'
+      # attributes['fancy_primary_key'] = 2020
+      #
+      # attributes['id']
+      # => 2020
+      #
+      # Additionally, symbols are always aliases of strings:
+      # attributes[:fancy_primary_key]
+      # => 2020
+      #
+      def [](key)
+        super(unalias(key))
+      end
+
+      def []=(key, value)
+        super(unalias(key), value)
+      end
+
+      def aliases
+        @aliases ||= {}
+      end
+
+      def unalias(key)
+        key = key.to_s
+        aliases[key] || key
+      end
+
+    end
+  end
+end
+